+1 to this
http://www.scotts.com/smg/gocat/lawn-fertilizer-products/cat50024
Step #1 is the blue bag for Crabgrass
Step #2 is the Yellow bag for Weeds
Step #3 is the Orange bag for bugs
Step #4 is the Goldish sometimes bag for Fall Weed & Feed. This is the most important step for next spring. Also, don't get the Marron one, that one doesn't have the weed killer.
The "step" bags go to the smaller distributors usually like Roush Hardware. The big box stores like Lowe's get "Turf Builder"
Also, never combine steps 1,2 or 4 (Fall Weed & Feed version) and grass seed, the fertilizer will kill the seeds.